Vincent is captured and held hostages by two scientists who stick him in a cage. Catherine considers a new job in Providence.

Father's past is revealed when he goes above for the first time in over thirty years to see a friend. When he gets to his friends office he finds his friend is dead. Father is then charged with murder.

Laura, a deaf-mute tunnel dweller, witnesses the murder of a police officer, for which another man is framed. She goes above with Catherine, but is kidnapped by the real murderers, who are also police officers. Cuffed to a pipe in the basement of the murderer's house, Laura taps out an SOS, which is heard by Pascal and Vincent rescues her. She decides to return Above to live.

Paracelsus, a former friend of Father's, sells an hallucinatory drug in the world above.

Paracelsus kidnaps Catherine, which causes Vincent to begin a quest to rescue her.

Laura, a deaf ex-tunnel dweller, falls in with a deaf street gang.

Catherine's father dies and Vincent allows her to come below to grieve. He also makes her go back above because he knows that she does not belong there no matter how he feels. Catherine finally agrees and goes back above.

Catherine finds out while visiting Joe in the hospital that she is pregnant. As she heads to her car in the parking garage she is kidnapped. Due to Vincent's recent illness he can not sense where she is. He knows nothing of the child that she carries. The kidnappers lock her in a cell. They want only the child. They think that if they take the baby they will get Vincent to emerge and that is exactly what they want. They continue to hold Catherine captive as Vincent frantically searches for her. It seems completely hopeless without his sense of her. Yet he vows to find her no matter the cost.

As the child grows inside of Catherine, Vincent begins to have strange dreams. He doesn't know what they are at first, but eventually he figures out that they are related to Catherine. He begins to look for her again. Meanwhile Catherine goes into labor. She tries to hide it by not making any noise. Eventually her captors figure it out and tie her down in a chair to deliver the baby. Vincent has entered the building where she is. Now all he has to do is find her. Catherine gives birth to a little boy. She begs to see him as Vincent frantically searches for her. They refuse to let her see the baby. They take the child and escape after they have given her a shot of poison that will kill her. Just as the helicoptor takes off Vincent reaches the roof, but he is too late. He still hasn't found Catherine. Suddenly he turns as he hears her call out to him. He runs to her as she begins to fall. She tells him that there is a child. He seems surprised, but now he knows that he is a father. As sh

Diana notices things in Catherine's apartment that have Vincent's name on them. She begins to realize that Vincent was her lover and probably the father of her child. She then decides to go to where Catherine is buried and wait for Vincent to do the same. One night it works. Vincent is sick and literally falls on top of Catherine's grave. Diana finds him and carries him back to her apartment where she nurses him back to health.